Apparatus for making spiral-rolled bars.



F. H. WILLIAMS.

APPARATUS FOR MAKING SPIRAL ROLLED BARS.

APPLICATION FILED SEPT.29, I913.

Patented Nov. 23, 1915.

APPARATUS FOR MAKING SPIRAL-ROLLED BARS.

Specification of Letters Patent.

Patented Nov. 23,1915.

Application filed September 29, 1913; Serial No. 792,273.

1 0 all whom it may concern Be it known that I, FRANK H. WILLIAMS, a citizen of the United States of America,residing at Buffalo, in the county of Erie and State of New York, have invented certain new and useful Improvements in Apparatus for Making Spiral-Rolled Bars, of which the following is a full, clear, and exact description.

My invention-relates generally-to apparatus for making metal bars having sp1rallydisposed threads, such as may be used in reinforcing concrete work.

As is well known to those skilled in the art, metal bars whichhave been used ferreinforcing concrete have been formed with spiral threads by twisting the bars. Thesebars are generally of polygonal cross-sectionor formed with a plurality of longitudinally extending ridges in order that the corners or ridges thereof mightform the threadsor twisted corners of the bar; this character have been sotwisted, while hot, (but have not been rolled on their surfaces during the twisting operation) it has been found that strains are set up in the metal of the bar which frequently give way to breaks after the bar is cold and put to use. Furthermore, it has. been found, by those skilled in the art, that when polygonal reinforcing-bars are molded in concrete mixtures, the concrete moves slightly away from the flat surfaces of the bar and is drawn in tightly against the corners thereof. This lack of contact of the cement with the'b'ar decreases the strength of the combination and it is oftenfound that thecement at the corners of the-bar is cracked, due to the ex--- cessive strain set up at the corners and the sharp edges thereof. Moreover, ithas been found that threads on a twisted bar which are more nearly at right angles with the axis of the bar give the best axial grip on the concrete. In order to produce this with a twisted square or rectangular bar, it is necessary to greatly increase the number of twists, and thus increase the uncertainty of the physical properties of the; finished twisted When bars of tensile strength of the finished product and also obviates any uncertainty as to the presence of strains in the finished product, which would be caused if the bar were produced by twisting the same. The bar which is produced by my apparatus has an oval crosssection which provides the best possible shaped surface for contact of the concrete, and also eliminates the danger of cracking the concrete at the corners. The rolling of my product is such as to bring the threads at a greater angle with the axis of the bar than is the case with the present twisted square bars, thus giving an increased axial grip on the concrete. The finished product is also straight throughout its length as it leaves the exit ends of the rolls.

Reference is to be had to the accompanying drawings, forming part of this specification, in which like characters of reference indicate like parts throughout the several views, of which:

Figure l is a plan view of the rolls of my apparatus, showing the upper roll in dotted lines and the lower roll in full lines and a bar passing th'erebetween in the process of being rolled. Fig. 2 is a sectional elevation of my apparatus, the section being taken of the lower roll, on line 22 of Fig. 1. Fig. 3 is a transverse section of the bar taken on line 3-3 of Fig. 1. Fig. 4 is atransverse superimposed,'one above the other, and have their axes at preferably right angles to'each other. Suitable means (not shown) are provided for rotatably mounting and driving these rolls in unison. of the rolls 5 and 6 respectively, are the enteringends of the rolls, and the ends 9 and 10 are the exit ends thereof. On each periphery of the rolls is provided. a series of circumferential ridges. The ridges 11, 12, 13, 14-, 15 and 16' startat theentrance ends and 8of the rolls, and, up to substantially the center, gradually increase in width from a very narrow ridge to substantially a width or size which is equal to the full width of the grooves on the bar as measured perpendicular to the helix. From substantially the center of the rolls to the The ends 7 and 8 lli) exit ends 9 and 10, the circumferential ridges 17 and 18 are of a width and a curvature substantially equal to the "uniform.

width and curvature of the contacting rolled surfaces of thebar as measured longitudinally. From the entrance and exit ends of the rolls the ridges decrease in diam eter as they approach a plane midway between the ends so that the general contour of the rolls is concav The narrow ridges l1 and 12 at the entrance end of the rolls are preferably knurled so as to permit the rolls to grasp the bar as it is, entering and feed it between and through the rolls 5' and 6.

Inthe drawings, 19 represents a bar passing through the rolls 1n the process of being rolled and having threads spirally formed thereon. This bar, asherembefore stated,"is of substantially round cross-section before being rolled. In this drawing, I show the end 20 of the bar as it is before being rolled, and the end 21 as it is after-being rolled. It will be noticed that from the entrance end of the rolls to substantially the center of the rolls, the bar has a groove gradually increasing in width.

.T he bar'is rolled with a double thread, each, starting at substantially 180 degrees apart.

is made by the ridge 11 on the lower roll.

As thebar continues to travel, thegroove 22 is engaged in succession by the ridge 12 of the lower-roll, the ridge 13 of the upper roll, the ridge 14c ofthe lower roll, the ridge 15 of the upper. roll, the ridge 16 of the lower roll,;the ridge 17 of the upperroll, r and then isengaged successively by the full width ridges 18 of the upper and lower rolls. The groove 23 is started by the ridge 11 of thelower roll and is engaged in succession by the ridge 12 of the upper roll, the ridge 13 of the lower roll, the ridge 14 of the upper roll, the ridge 15 of the lower roll, the ridge 16 of the upper roll, the

ridge 17 of the lower roll and then successively by the full width ridges '18 of the formed in the product.

oval or elliptical cross-section.

' The pitch of the circumferential ridges formed on'the periphery of my rolls, as measured along the line of travel of the bar, is such as to correspond to the uniform pitch of the thread of the bar, and the gradually decreasing width of grooves 26 forms clearance spaces for the unrolled surface of the bar while it is passing through between substantially the first half of the rolls.

lVhile I have shown and described my apparatus as applied to rolling of metal bars, it is obvious that the same may be applied to the rolling of other products than those herein referred to, such other products I having characteristics similar to those herein described. The angular relation of the axes of the rolls may be varied and made to suit any desired lead of the thread on the bar. These and other modifications of the details herein shown and described may be made without departing from the spirit of my invention as set forth in the appended claims, and I do not wish to be limited to the exact embodiment herein shown and described.

Having thus described my invention, what I claim is:

1. An apparatus for making spiral-rolled bars, comprising two superimposed rolls having their axes at an angle to each other, the periphery of each roll being provided with a series of circumferential ridges, said ridges decreasing in diameter as they approach a plane midway between the end of the rolls, whereby the general contour of the rolls is concave.

2. An apparatus for making spiral-rolled bars, comprising two superimposed rolls having their axes at an angle to each other, the periphery of each roll being provided with a series of circumferential ridges having a pitch, measured along the line of travel of the bar, which is substantially equal to the maximum pitch of the bar, said ridges decreasing in diameter as they approach a plane midway between the end of the rolls, whereby the general contour of the rolls is concave.

An apparatus for making spiral-rolled bars, comprising two superimposed rolls having their axes at an angle to each other, the periphery of each roll being provided with a'series of circumferential ridges, said ridges gradually increasing in width from the entrance end of each roll to a width near the center of each of said rolls, which, when measured along the axis of the bar is substantially equal to the full pitch of the bar, the first of the narrow ridges at the entrance end of the rolls being knurled, and said ridges decreasing in diameter as they approach a plane midway between the ends of the rolls, whereby the general contour of the rolls is concave.

4. An apparatus for making spiral-rolled bars, comprising two superimposed rolls having their axes at an angle to each other, the periphery of each roll being provided with a series of circumferential ridges, said ridges gradually increasing in Width from the entrance end of each roll to a maximum width near the center of each of said rolls, which, when measured along the axis of the bar is substantially equal to the full pitch of the bar, said ridges decreasing in diameter as they approach a plane midway between the ends of the rolls, whereby the general contour of the rolls is concave.

5. An apparatus for making spiral-rolled bars, comprising two superimposed rolls having their axes at an angle to each other, the periphery of each roll being provided with a series of circumferential ridges, said ridges gradually increasing in width from the entrance end of each roll to a width near the center of each of said rolls, which, when measured along the axis of the bar is substantially equal to the full pitch of the bar, the remaining ridges from substantially the center of the rolls to the exit end of each being of a width corresponding to the width of the uniform, finished grooves in the bar, as measured along its line of contact with the rolls, and said ridges decreasing in diameter as they approach a plane midway between the end faces of the rolls, whereby the general contour of the rolls is concave.

In testimony whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

FRANK H. WILLIAMS.

Witnesses:

J. WM. ELLIS, VVALTER H. KELLEY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

